If you're having trouble connecting your Gmail account to Outlook or Mail for Windows 10, this might be due to your Gmail settings. Follow the steps below to change your Gmail settings and fix the issue.

Step 1: Enable IMAP
IMAP must be enabled in Gmail before you can connect your account.

In a browser, go to Gmail.com.

Select Settings > Settings.

Select the Forwarding and POP/IMAP tab.

Under IMAP Access, select Enable IMAP.

Select Save Changes.

Step 2: Change SMTP & other settings in your email client
Open Manage Connected Accounts in Outlook.com

Use the table below to check you have the correct information:

Incoming mail (IMAP) server

imap.gmail.com

Requires SSL: Yes

Port: 993

Outgoing mail (SMTP) server

smtp.gmail.com

Requires SSL: Yes

Requires TLS: Yes (if available)

Requires Authentication: Yes

Port for SSL: 465

Port for TLS/STARTTLS: 587

Full name or display name

Your name

Account name, username or email address

Your full email address

Password

Your Gmail password

Step 3: Enable folders
Outlook and Mail for Windows 10 need access to your folders in Gmail. Make sure that the folders are set to show in IMAP.

In a browser, go to Gmail.com.

Select Settings > Settings.

Select the Labels tab.

Make sure that Show in IMAP is selected for Inbox, Sent Mail, Trash, and All Mail.

You can also select Show in IMAP for other labels that you want to see in Outlook or Mail for Windows 10.

Step 4: Refresh Outlook or Mail for Windows 10
Once you've enabled IMAP in Gmail and set your Gmail folders to show in IMAP, refresh Outlook or Mail for Windows 10.

Note: It can take up to 15 minutes for syncing to refresh.

Outlook.com and Outlook on the web:

Select the refresh button in your browser's URL bar.

Outlook 2016 for Mac:

On the ribbon, select Organize > Sync Folder.

Mail for Windows 10:

Above the message list, select Sync this view .

I hope these steps will be useful to resolve your issues.
Matt Henry